easy option:
remove hard disk from computer
set the drive as slave
hook up to another machine (preferably one with a burner)
detect the disk in bios, then boot.
transfer any files you require, burn to CD(s)
remove drive, set as master, replace into orignial machine
format and reload, then transfer the files of the cd(s) you burnt.
Job done
edit:
you may want to scan the drive while it's out of the original machine - you never know but it might pick something up.